Steak, Caramelized Onion, Mushroom and Cheddar Panini

I am finally all caught up with work for the day and it is only lunchtime! Since I had some extra time, I decided to make a panini with London broil leftover from dinner last night. Delicious!

Ingredients: 
Recipe and photo by cuckooking.blogspot.com

• Good bread - I use seedless rye bread from the bakery
• Onion, chopped
• 1 tbsp olive oil
• 1 tsp minced garlic
  
• Button mushrooms, sliced
• Sea salt, to taste
• Steak - I used leftover from dinner. Deli roast beef would be a good substitute!
• Cheddar cheese
• Dijon mustard

Directions:

In a skillet over medium heat, caramelize onion in olive oil and minced garlic. Add sliced button mushrooms seasoned with sea salt and cook to desired doneness. Add leftover steak in the pan until warmed through.Place everything inside bread and add cheddar cheese and Dijon mustard to taste. Cook in panini maker for 5 minutes.